Question

Is there a way to influence the kind of quotes that python uses when casting a tuple/list to string?

For some NLP software I get tuples somewhat like this:

("It", ("isn't", "true"))

I want to cast it to a string and simply remove all double quotes and commas:

(It (Isn't true))

However, python is having its way with the quotes, it seems to prefer single quotes:

>>> print str(("It", ("Isn't" ,"true")))
('It', ("Isn't", 'true'))

, making my life more difficult. Of course I could write my own function for printing it out part-by-part, but there is so much similarity between the representation and native python tuples.

Answer 1

You can’t rely on the exact representation that repr uses. I’d just do as you thought and write your own function — I don’t see it being more than a handful of lines of code. This should get you going.

def s_exp(x):
    if isinstance(x, (tuple, list)):
        return '(%s)' % (' '.join(map(s_exp, x)))
    return str(x)

Writing your own function may be inevitable: if your strings contain brackets “(“, “)” or spaces ” ” then you’ll need some form of escaping to produce well-formed s-expressions.